Zinc and method of purifying and improving the same.



UNITED STATES PATENT OFFICE.

AUGUSTE J. 30881, OF NIAGARA FALLS, NEW YORK, ASSIGNOR TO THE TITANIUMALLOY MANUFACTURING COMPANY, OF NEW YORK, N. Y.,, A CORPORATION OFMAINE.

ZINC AND METHOD OF PURIFYING AND IMPROVING THE SAME.

No Drawing.

Patented Mar. 19, 1912.

To all whom it may concern:

Be it known that I, AuoUsTE J. Rosst, a citizen of the United States,residing at Niagara Falls, in the county of Nia ara and State of NewYork, have invente certain new and useful Improvements in Zinc andMethods of Purifying and Improving the Same, of which the following is aspecification.

Zinc, while in molten state, absorbs gaseous elements or compounds,which are dissolved in the metal and retained therein as it solidifiesduring cooling. For instance oxygen from the atmosphere is thus absorbedand, to an extent, combines chemically with other elements present formng oxids thereof, as for example oxids of zlnc, which together withoxygen if any remalning uncombined are found occluded 1n the mass of thesolidified metal. Moreover throughout said mass are also found, to

greater or less extent, other substances, or

compounds, foreign to zinc, as for instance drosses, or slags, whichowing to their comparative infusibilit-y or lack of fluidity or both areunable to rise out of the 'molten metal and conse uently may to greateror less extent remain entangled therein after itssolidification.

The aforesaid foreign elements and compounds are usually unhomogeneouslydistributed in uncontrollable locations throughout the mass of themetal, thus producing blow-holes or other cavities devoid of zinc whichproportionately, and undesirably, impair the metallic continuity of thev mass, thus diminishing its efficiency for many of its presentindustrial uses, as for example in galvanizing so called in which it isparticularly important that the coating of zinc applied shall becontinuous and impervious.

I I believe that it has hitherto proved impossible to produce or meltzinc, at least on an industrial as distinguished from a laboratoryscale, involving refinings commercially impracticable, wlthoutincorporation and retention in the resulting metallic mass of suchforeign elements and compounds, and to such extent, as to preclude itspossession in theoretically normal degree of desirable physicalproperties to be expected as characterizing pure zinc.

The object of my present invention is to provide methods of treatmentwhereby with such economy, simplicity and speed as to be practicable onan industrial scale, zinc possessing superior properties may be producedin masses substantially devoid of undesired foreign elements andcompounds including slags. I attain said objects by means of my novelprocedure hereinafter described, viz :I have discovered that if to zinc,as now produced in the industrial arts, and While it is melting ormolten, there be added merely enough titanium to satisfy chemicalaflinity therefor of all such undesired elements present, whether infree or combined state, all these, including drosses and sla and,besides, such titanium so added, Wlll be eliminated from the moltenmass, the re-' sulting product being substantially solid pure zinc.

My said invention comprises the following procedures: To a bathcomprising the meltlng, or molten, zinc to be treated. ,I may unpart thepresence of metallic titanium in such small quantity, proportioned asnearly as possible, as is suflicient merely to satisfy the chemicalaffinities therefor of the said undesired elements and compoundspresent. The said proportion of titanium required may be determined inany convenient manner, as, for example, by usual calculations based onthe kinds and proportions of said undesired elements and compounds asdisclosed by preliminary chemical analyses of specimens of the mass ofany given type of commercial or other zinc desired to be treated; or byvarying tentatively the proportions of titanium so added untilattainment of a final roduct containing substantially neither saidundesired ele-' ments and compounds nor substantially any titanium, theproportion of latter used with such result being that required forpurification of the particular type of zinc mass so tested. The titaniumis so added preferably in its elemental or metallic form, as, forexample, an alloy of titanium with some metal, preferably in most cases,an alloy of titanium with zinc havin a content of 10% to 12% or thereaout of titanium and producible on an industrial scale for example bymeans of the method specified in my Letters Patent No. 979,393,,

dated Dec. 20,1910. In some instances, where presence of some metalother than zinc in the final product is not objectionable or is desired,the titanium may be added in the form of its alloy with such othermetal, as, for example, with iron, this being the alloy of my LettersPatent No. 609,466, dated August 23, 1898; or with copper, this beingthe alloy of my Letters Patent No. 7 00,244, dated May 20, 1902,reissued March 17, 1908, No. 12,764..

Addition of the titanium in other forms, as for instance that of itsoxid may, where conditions are developed enabling the same to ultimatelyyield to the zinc the required proportion of metallic titanium, bepracticed without departing from my invention. The titanic materialemployed may be preferably added in such sub-divided state as willfacilitate to an extent its distribution relatively to the mass ofmolten zinc.

The titanic material may be charged into the crucible or other containerof the bath prior to introduction thereinto of the melting or moltenzinc, or it may be charged upon the latter, in which case a covering ofmolten slag or the like may be superimposed as per my Letters Patent No.877,518, dated January 28, 1908 to prevent reactions with constituentsof the atmosphere. It

appears, however, that, notwithstanding the higher'melting point and thelower specific gravity of titanium as compared with zinc, elementaltitanium in-the aforesaid proportion, however added, is able to reach,and react upon, or chemically combine with, all undesired elements andcompounds resent in the mass of molten zinc. After a dition of thetitanium, the temperature of the bath ismaintained at fully that of themelting point of zinc and will be found to be somewhat heightened by thesaid chemical reactions and combinations attributable to the presence ofthe titanium, and until these have fully taken place, the time requiredfor these being usually but a few minutes.

The titanium appears to not only combine chemically with undesiredelements present, such as free oxygen and nitrogen, but also, by reasonof its intenser aflinity for such elements, to reduce compounds thereof,such as oxid of zinc for example, and to combine with the oxygen thusliberated to form oxid of titanium, the presence of which in the bathimparts to therein occluded drosses or slags sufficient fluidity toinsure their rising properly to the surface of the molten mass, andbesides this, in cases in which the titanium added is insufficient inamount to both combine with undesired elements and in addition tocompletely deoxidize the entire amount of oxid of zinc present, thetitanium oxid already formed as aforesaid will proceed to furthercombine with such remain ing undecomposed oxids of zinc to, form aunobjectionable or desirable.

removal at expenditure of" less titanium.

than theoretically required for combination with all undesired elementsand-compounds present.

After the aforesaid operations the molten zinc may be tapped out andcast in the usual manner.

It will be understood that while a final zinc product free fromtitaniumas well as titanium in the resulting product may be Such instances maybe those in which the proportion of titanium remaining in the finalproduct is less than say 1% being an amount insufiicient to justify itsdesignation as an al- 10y of titanium in the-usual commercial sense, ordependence on such small amount of titanium for purposes other than toimprove said product itself. Such instances I regard as being withinthepurview of my present improvements, the presence of such smallpercentages of titanium imparting improved'physical properties and alsotending to prevent absorption of gaseous impurities whenever the zinccontaining it is remelted for any urpose. To retain said smallpercentage of titanium in the product it is only necessary to increase.accordingly the proportioned amounts of titanium added as hereinbeforedescribed.

My process results in impartin to the zinc thereby-treated the peculiaristinctly crystalline structure desired in zinc and often characteristicof the most carefully and expensively refined specimens of that metalthough notably absent in the usual zinc of commerce.

The treatment of zinc as per my above described invention results in anovel final product which is characterized as being a continuously solidmass consisting throughout of substantially pure metallic zinc; as beingsubstantially devoid of undesired elements or compounds includingdrosses and slags; as containing less than 1% of titanium; as free fromblow-holes and other physical imperfections due to presence or action ofelements and substances otherthan zinc, and as of greater density andtensile strength and possessing a highly crystalline structure.

What I claim as new and desire to secure by Letters Patent is thefollowing, viz

1. The method of improving the properties of zinc which consists inadding thereto while molten titanium in amount su'f nium in amountsuflicient to result in a final 4. As a new article a metallic body com-10 product containing titanium not to exposed prcponderatingly of zincand containceed 1%. ing titanium not to exceed 1%.

3 The method of improving the prop- 5. As a new article zinc containingtitaerties of zinc which consists in adding therenium not to exceed 1%.to While molten an alloy containing zinc AUGUSTE J. ROSSI. and titaniumin amount sufficient to result Witnesses: in a final product containingtitanium not WALTER D. EDMONDS,

to exceed 1%. GEORGE G. MEASURES.

